Method for preferentially extracting lithium in positive electrode material of waste lithium ion battery through mechanical activation reinforced CO2 pressurized water leaching
Through mechanical activation, the CO2 pressurized water immersion method is strengthened, and the crystal structure of the positive electrode material of the lithium-ion battery is destroyed. The weak acid environment formed by CO2 dissolved in water is preferred to leach lithium, which solves the problems of high lithium loss and poor selectivity in the prior art, and achieves an efficient and green lithium extraction process.
Patent Information
- Application Number
- CN202510745985.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-05
- Publication Date
- 2025-08-15
AI Technical Summary
The prior art has problems such as high lithium loss, low product purity, high energy consumption, exhaust gas emissions and equipment corrosion when extracting lithium from waste lithium-ion batteries, especially when lithium leaching is preferred.
The mechanical activation-enhancing CO2 pressurized water immersion method is used to destroy the crystal structure of the positive electrode material of the lithium-ion battery through a ball mill, forming a weak acid environment for high-pressure hydrothermal reaction, and using CO2 to dissolve in water to preferentially leach lithium to avoid dissolution of metals such as nickel, cobalt, manganese, and aluminum.
High selective leaching of lithium is achieved, which significantly shortens the process of preparing battery-grade lithium carbonate, reduces the loss of lithium, and has a green and environmentally friendly process, which meets economic and environmental protection requirements.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of secondary resource recycling and utilization, and specifically relates to a method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanically activating and strengthening CO2 pressurized water immersion. Background Art
[0002] In recent years, the new energy industry has developed rapidly. The service life of lithium-ion batteries is generally 3 to 8 years, and the number of waste lithium-ion batteries has also increased sharply. Waste lithium-ion batteries contain rich valuable metals such as lithium, nickel, cobalt, manganese, aluminum, etc., which is a high-value urban mineral resource. The recycling of waste lithium-ion batteries has also become a current research hotspot. The current recycling method is to achieve full leaching of valuable metals or preferential leaching of lithium through pyrolysis, hydrolysis and combined methods, and then leaching nickel, cobalt, manganese and aluminum. However, the existing methods have the following problems: (1) Full leaching of valuable metals: Valuable metals are leached out simultaneously through acid and reducing agent, but lithium is often extracted last. Due to precipitation and extraction entrainment, lithium loss is usually around 20%. In addition, saturated sodium carbonate solution needs to be added when preparing lithium carbonate, which produces a large amount of high-concentration salt wastewater, and the lithium carbonate product contains Na + and SO4 2- , it is difficult to reach the standard of battery-grade lithium carbonate and requires further processing, which is a long process.
[0003] (2) Prioritize lithium leaching: Lithium is converted into soluble lithium salts through pyrolysis, hydrolysis and pyrolysis-hydrolysis combined, while nickel, cobalt, manganese and aluminum exist in the form of single substances or oxides. The traditional pyrolysis roasting temperature is often above 1000 °C, and lithium enters the slag phase containing CaO, SiO2 and MnO2, which has low grade and is difficult to further extract lithium. This part of lithium is usually discarded. Therefore, many researchers have developed salt roasting to reduce the roasting temperature and extract high-value lithium, but the roasting temperature is usually above 400 °C, and it is inevitable to produce Cl2, NO x and SO x Other methods, such as wet methods using hydrochloric acid, nitric acid, and sulfuric acid at high temperature and high pressure, can also achieve preferential lithium extraction. However, these methods also present issues such as equipment corrosion and leaching selectivity in strong acid environments. Therefore, high energy consumption, toxic waste gas emissions, selectivity, and equipment corrosion are the pain points of current preferential lithium extraction methods.
[0004] Therefore, in response to the above problems, there is an urgent need to develop new methods for extracting valuable metals from waste lithium-ion batteries. Summary of the Invention
[0005] In order to solve the problems existing in the existing waste lithium-ion battery recycling industry, such as high lithium loss, low product purity, high energy consumption, waste gas emissions, and equipment corrosion, the present invention provides a method for preferentially extracting lithium from the positive electrode materials of waste lithium-ion batteries by mechanical activation-enhanced CO2 pressurized water immersion. The method only uses CO2 dissolved in water to form a weak acid environment to preferentially extract lithium. The process is green and environmentally friendly, with a short extraction process and high selectivity.
[0006] A method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water leaching comprises the following steps: (1) Place the waste lithium-ion battery positive electrode material and grinding balls into a ball mill, and then perform a mechanical activation reaction in the ball mill. After the reaction is completed, the activated material is obtained by screening; (2) Mixing the activated material and water to form a slurry and placing it in a high-pressure reactor, controlling the temperature in the reactor and introducing a gas containing CO2 to perform a high-pressure hydrothermal reaction, wherein the temperature is 160-260 °C, the pressure is 2.8-7 MPa, and the reaction time is 1-6 h; (3) After the reaction is completed, the solid and liquid are separated to obtain a lithium leaching solution and a lithium-depleted slag, wherein the lithium leaching solution is a LiHCO3 solution, which can be used to prepare battery-grade lithium carbonate after thermal decomposition.
[0007] Preferably, in step (1), the cathode material of the waste lithium-ion battery is at least one of a nickel cobalt manganese oxide material, a lithium cobalt oxide material, a lithium manganese oxide material and a nickel cobalt aluminum oxide material.
[0008] Preferably, in step (1), the diameter of the grinding balls is 3 to 12 mm.
[0009] Preferably, in step (1), in the mechanical activation reaction, the mass ratio of the grinding balls to the waste lithium-ion battery positive electrode material is 5:1-50:1 (g / g).
[0010] Preferably, in step (1), the mechanical activation reaction speed is 100-600 rpm.
[0011] Preferably, in step (1), the mechanical activation reaction time is 10-180 min.
[0012] Preferably, in step (2), the volume percentage content of CO2 in the CO2-containing gas is 20-100%, and the CO2-containing gas is CO2 gas, or a mixture of CO2 and any one of O2, N2, CO, air, and inert gas, or industrial waste gas containing CO2.
[0013] Preferably, in step (2), the solid-to-liquid ratio is 10-500 g / L.
[0014] Preferably, in step (3), the delithiation slag contains at least one of nickel, cobalt, manganese and aluminum, and the corresponding metal salt can be prepared based on existing means.
[0015] Compared with the prior art, the advantages of the present invention are: The present invention innovatively introduces mechanical activation to enhance CO2 pressurized water leaching to preferentially and selectively extract lithium from waste lithium-ion positive electrode materials. Mechanical activation effectively destroys the crystal structure of waste lithium-ion positive electrode materials, enhances their surface activity, and reduces the reaction activation energy, thereby lowering the temperature and pressure of the high-pressure hydrothermal reaction. The weakly acidic environment formed by CO2 dissolving in water preferentially and selectively leaches lithium, while not leaching metal elements such as nickel, cobalt, manganese, and aluminum. This achieves highly selective leaching of lithium and produces a lithium leaching solution composed of LiHCO3. Battery-grade lithium carbonate can be prepared after thermal decomposition, significantly shortening the process for preparing battery-grade lithium carbonate and reducing lithium loss. This method conforms to the concept of green economy and environmental protection and has broad industrial application prospects. DETAILED DESCRIPTION
[0016] Example 1 This embodiment provides a method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water leaching. The processed waste lithium-ion battery positive electrode material is lithium nickel cobalt manganese oxide, and the composition is shown in Table 1.
[0017] Table 1 The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 200 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 30 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 10 g of activated material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 190 °C, the reaction pressure was 3.2 MPa, and the reaction time was 1 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0018] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 95.73%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the delithiation residue was treated using existing technologies to obtain the corresponding metal salts.
[0019] Example 2 This embodiment provides a method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water leaching. The waste lithium-ion battery positive electrode material to be processed is lithium nickel cobalt manganese oxide, and its composition is the same as that of Example 1.
[0020] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 200 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 30 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 10 g of activated material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 190 °C, the reaction pressure was 4 MPa, and the reaction time was 3 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0021] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 97.89%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the corresponding metal salts were obtained by processing the lithium-removal residue using existing technologies.
[0022] Example 3 This embodiment provides a method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water leaching. The processed waste lithium-ion battery positive electrode material is lithium cobalt oxide, and the composition is shown in Table 2.
[0023] Table 2 The specific steps are: (1) 12 g of waste lithium-ion battery cathode material and 240 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 50 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 12 g of activated material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 220 °C, the reaction pressure was 4 MPa, and the reaction time was 2 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0024] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Co, Fe, and Al. Calculated Li leaching rates were 94.46%, while Co, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the de-lithiation residue was treated using existing technologies to obtain the corresponding metal salts.
[0025] Example 4 This embodiment provides a method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water leaching. The processed waste lithium-ion battery positive electrode material is lithium manganese oxide, and the composition is shown in Table 3.
[0026] Table 3 The specific steps are: (1) 20 g of waste lithium-ion battery cathode material and 400 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, mechanical activation reaction was carried out in a ball mill with a reaction time of 60 min and a rotation speed of 600 rpm. After the reaction, the activated material was obtained by screening. (2) 20 g of activated material and 100 mL of water were mixed to form a slurry and placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 240 °C, the reaction pressure was 6 MPa, and the reaction time was 4 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0027] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Mn, Fe, and Al. Calculated Li leaching rates were 92.88%, while Mn, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate can be obtained by pyrolysis of the lithium leaching solution, and the de-lithiation residue can be processed using existing technologies to obtain the corresponding metal salts.
[0028] Example 5 This embodiment provides a method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water leaching. The processed waste lithium-ion battery positive electrode material is lithium nickel cobalt aluminum oxide, and the composition is shown in Table 4.
[0029] Table 4 The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 200 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 30 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 10 g of activated material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 200 °C, the reaction pressure was 3.5 MPa, and the reaction time was 2 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0030] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Ni, Co, Fe, and Al. Calculated Li leaching rates were 94.66%, while Ni, Co, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the de-lithiation residue was treated using existing technologies to obtain the corresponding metal salts.
[0031] Comparative Example 1 This comparative example provides a method for extracting lithium from anode materials of waste lithium-ion batteries. The cathode materials of waste lithium-ion batteries to be processed are lithium nickel cobalt manganese oxide, and the composition is the same as that of Example 1.
[0032] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for a high-pressure hydrothermal reaction. The reaction temperature was 190 °C, the reaction pressure was 4 MPa, and the reaction time was 3 h. (2) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0033] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 92.44%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the de-lithiation residue was treated using existing technologies to obtain the corresponding metal salts.
[0034] Compared with Example 2, this comparative example did not undergo mechanical activation treatment, and the Li leaching rate was significantly reduced.
[0035] Comparative Example 2 This comparative example provides a method for extracting lithium from anode materials of waste lithium-ion batteries. The cathode materials of waste lithium-ion batteries to be processed are lithium nickel cobalt manganese oxide, and the composition is the same as that of Example 1.
[0036] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for a high-pressure hydrothermal reaction. The reaction temperature was 230 °C, the reaction pressure was 4 MPa, and the reaction time was 3 h. (2) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0037] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 96.32%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the delithiation residue was treated using existing technologies to obtain the corresponding metal salts.
[0038] Compared to Example 2, this comparative example did not undergo mechanical activation, but increased the reaction temperature of the high-pressure hydrothermal reaction, resulting in a similar lithium leaching rate. Compared to Comparative Example 1, this comparative example significantly improved the lithium leaching rate by increasing the reaction temperature of the high-pressure hydrothermal reaction. Therefore, mechanical activation can lower the reaction temperature for CO2-pressurized water leaching to preferentially extract lithium from waste lithium-ion battery cathode materials.
[0039] Comparative Example 3 This comparative example provides a method for extracting lithium from anode materials of waste lithium-ion batteries. The cathode materials of waste lithium-ion batteries to be processed are lithium nickel cobalt manganese oxide, and the composition is the same as that of Example 1.
[0040] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for a high-pressure hydrothermal reaction. The reaction temperature was 190 °C, the reaction pressure was 7 MPa, and the reaction time was 3 h. (2) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0041] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 95.15%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the delithiation residue was treated using existing technologies to obtain the corresponding metal salts.
[0042] Compared to Example 2, this comparative example did not undergo mechanical activation, but increased the reaction pressure of the high-pressure hydrothermal reaction, resulting in a similar Li leaching rate. Compared to Comparative Example 1, this comparative example increased the reaction pressure of the high-pressure hydrothermal reaction, significantly improving the Li leaching rate. Therefore, mechanical activation can reduce the reaction pressure required for CO2-pressurized water leaching to preferentially extract lithium from waste lithium-ion battery cathode materials.
[0043] Comparative Example 4 This comparative example provides a method for extracting lithium from anode materials of waste lithium-ion batteries. The cathode materials of waste lithium-ion batteries to be processed are lithium nickel cobalt manganese oxide, and the composition is the same as that of Example 1.
[0044] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for a high-pressure hydrothermal reaction. The reaction temperature was 190 °C, the reaction pressure was 4 MPa, and the reaction time was 6 h. (2) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0045] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 94.44%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%. Battery-grade lithium carbonate was obtained by pyrolysis of the lithium leaching solution, and the delithiation residue was treated using existing technologies to obtain the corresponding metal salts.
[0046] Compared to Example 2, this comparative example did not undergo mechanical activation, but extended the high-pressure hydrothermal reaction time, resulting in a similar Li leaching rate. Compared to Comparative Example 1, this comparative example extended the high-pressure hydrothermal reaction time, significantly improving the Li leaching rate. Therefore, mechanical activation can shorten the reaction time for CO2-pressurized water leaching to preferentially extract lithium from waste lithium-ion battery cathode materials.
[0047] Comparative Example 5 This comparative example provides a method for extracting lithium from waste lithium-ion battery positive electrode materials. The waste lithium-ion battery positive electrode materials treated are the same as those in Example 1.
[0048] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 200 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 30 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 10 g of activated material and 100 mL of water were mixed to form a slurry and placed in a high-pressure reactor. The reaction temperature was 190 °C, Ar2 was introduced into the reactor to make the reaction pressure 3.2 MPa, and the reaction time was 1 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0049] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect the presence of metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 26.73%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%.
[0050] Compared with Example 1, in this comparative example, CO2 gas was not introduced during the high-pressure hydrothermal reaction, and the Li leaching rate was greatly reduced.
[0051] Comparative Example 6 This comparative example provides a method for extracting lithium from waste lithium-ion battery positive electrode materials. The waste lithium-ion battery positive electrode materials treated are the same as those in Example 1.
[0052] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 200 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 30 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 10 g of activated material and 100 mL of water were mixed to form a slurry and placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 150 °C, the reaction pressure was 3.2 MPa, and the reaction time was 1 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0053] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect the presence of metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 67.73%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%.
[0054] Compared with Example 1, the reaction temperature was lowered during the high-pressure hydrothermal reaction in this comparative example, and the Li leaching rate was greatly reduced.
[0055] Comparative Example 7 This comparative example provides a method for extracting lithium from waste lithium-ion battery positive electrode materials. The waste lithium-ion battery positive electrode materials treated are the same as those in Example 1.
[0056] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 200 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 30 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 10 g of activated material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 190 °C, the reaction pressure was 3.2 MPa, and the reaction time was 0.5 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0057] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect the presence of metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 87.73%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%.
[0058] Compared with Example 1, the reaction time of the high-pressure hydrothermal reaction in this comparative example was shortened, and the leaching rate of Li was greatly reduced.
[0059] Comparative Example 8 This comparative example provides a method for extracting lithium from waste lithium-ion battery positive electrode materials. The waste lithium-ion battery positive electrode materials treated are the same as those in Example 1.
[0060] The specific steps are: (1) 10 g of waste lithium-ion battery cathode material and 200 g of grinding balls were placed in a ball mill, of which 3 mm and 8 mm grinding balls accounted for 70% and 30% respectively. Then, a mechanical activation reaction was carried out in a ball mill with a reaction time of 30 min and a rotation speed of 500 rpm. After the reaction, the activated material was obtained by screening. (2) 10 g of activated material and 100 mL of water were mixed to form a slurry, which was then placed in a high-pressure reactor. CO2 gas was introduced into the reactor for high-pressure hydrothermal reaction. The reaction temperature was 190 °C, the reaction pressure was 2.7 MPa, and the reaction time was 1 h. (3) After the reaction is completed, the solid and liquid are separated to obtain lithium leaching solution and lithium de-lithium slag.
[0061] Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used to detect the presence of metal elements such as Li, Ni, Co, Mn, Fe, and Al. Calculated Li leaching rates were 85.25%, while Ni, Co, Mn, Fe, and Al leaching rates were all 0%.
[0062] Compared with Example 1, the reaction pressure in this comparative example was lowered during the high-pressure hydrothermal reaction, and the Li leaching rate was greatly reduced.
Claims
1. A method for preferentially extracting lithium from waste lithium-ion battery cathode materials by mechanically activated CO2 pressurized water immersion, characterized in that: The following steps are involved: (1) Place the waste lithium-ion battery positive electrode material and grinding balls into a ball mill, and then perform a mechanical activation reaction in the ball mill. After the reaction is completed, the activated material is obtained by screening; (2) Mixing the activated material and water to form a slurry and placing it in a high-pressure reactor, controlling the temperature in the reactor and introducing a gas containing CO2 to perform a high-pressure hydrothermal reaction, wherein the temperature is 160-260 °C, the pressure is 2.8-7 MPa, and the reaction time is 1-6 h; (3) After the reaction is completed, the solid and liquid are separated to obtain a lithium leaching solution and a lithium-depleted slag, wherein the lithium leaching solution is a LiHCO3 solution, which can be used to prepare battery-grade lithium carbonate after thermal decomposition.
2. The method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, characterized in that: In step (1), the positive electrode material of the waste lithium-ion battery is at least one of a nickel cobalt manganese oxide material, a lithium cobalt oxide material, a lithium manganese oxide material and a nickel cobalt aluminum oxide material.
3. The method for preferentially extracting lithium from waste lithium-ion battery cathode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, characterized in that: In step (1), the diameter of the grinding balls is 3 to 12 mm.
4. The method for preferentially extracting lithium from waste lithium-ion battery cathode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, wherein: In step (1), in the mechanical activation reaction, the mass ratio of the grinding balls to the waste lithium-ion battery positive electrode material is 5:1-50:1 (g / g).
5. The method for preferentially extracting lithium from waste lithium-ion battery positive electrode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, characterized in that: In step (1), the mechanical activation reaction speed is 100-600 rpm.
6. The method for preferentially extracting lithium from waste lithium-ion battery cathode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, characterized in that: In step (1), the mechanical activation reaction time is 10-180 min.
7. The method for preferentially extracting lithium from waste lithium-ion battery cathode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, characterized in that: In step (2), the volume percentage of CO2 in the CO2-containing gas is 20-100%, and the CO2-containing gas is CO2 gas, or a mixture of CO2 and any one of O2, N2, CO, air, and inert gas, or industrial waste gas containing CO2.
8. The method for preferentially extracting lithium from waste lithium-ion battery cathode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, characterized in that: In step (2), the solid-liquid ratio is 10-500 g / L.
9. The method for preferentially extracting lithium from waste lithium-ion battery cathode materials by mechanical activation-enhanced CO2 pressurized water immersion according to claim 1, characterized in that: In step (3), the delithiation slag contains at least one of nickel, cobalt, manganese and aluminum.